Method for manufacturing lenses, in particular for an imager comprising a diaphragm

Abstract

A method for manufacturing a lens of a polymer material, includes producing in the core of the lens or on the surface of the latter at least one opaque zone having an optical function, by locally degrading the molecular structure of the polymer material using a beam of laser light. Example application is provided in particular but not exclusively to CMOS imagers.

1. A method for manufacturing a lens of a polymer material, the method comprising:
 producing in or on the lens at least one opaque zone having an optical function, 
 wherein said at least one opaque zone is made opaque by locally degrading a molecular structure of the polymer material at said at least one opaque zone using a beam of laser light, and 
 wherein said at least one opaque zone, of the lens thus obtained, includes the polymer material having said degraded molecular structure, wherein said at least one opaque zone is located within said lens at a distance from a surface of said lens. 
 
   
   
     2. The method according to  claim 1  wherein the laser beam is applied to the lens using a variable focus device comprising a wide-angle lens, enabling a distance between a zone to be degraded and a surface of the lens to be chosen. 
   
   
     3. The method according to  claim 1  wherein the at least one opaque zone forms a diaphragm. 
   
   
     4. The method according to  claim 1 , further comprising producing a plurality of contiguous opaque zones forming a diffraction grating having an optical filter function. 
   
   
     5. The method according to  claim 1  wherein the at least one opaque zone is produced during manufacturing the lens in which the lens has a flat face, by applying the laser beam to the flat face. 
   
   
     6. The method according to  claim 5  wherein the production of the at least one opaque zone is followed by rounding the flat face of the lens. 
   
   
     7. The method according to  claim 1 , comprising manufacturing at least two lenses, producing at least one opaque zone in at least one of the two lenses, and assembling the two lenses to form a complex lens. 
   
   
     8. A method for manufacturing an integrated micro-module for capturing images, the method comprising:
 manufacturing at least one imager on a semiconductor substrate; 
 manufacturing at least one lens; 
 producing in or on the lens at least one opaque zone in accordance with the method according to  claim 1 ; and 
 assembling the lens directly onto the semiconductor substrate, without using any lens-holder frame. 
 
   
   
     9. A method for collectively manufacturing integrated optical micro-modules, the method comprising:
 collectively manufacturing a plurality of imagers on a semiconductor wafer; 
 collectively manufacturing a plurality of lenses on at least one plate having one or more layers of polymer material and forming a lens wafer; 
 producing at least one opaque zone in or on lenses out of the plurality of lenses, in accordance with the method according to  claim 1 ; 
 assembling the lens wafer and the semiconductor wafer, so that each lens is opposite an imager; and 
 cutting out the assembly to obtain a plurality of integrated optical micro-modules. 
 
   
   
     10. A formed lens of a polymer material, the lens comprising at least one opaque zone having an optical function, the at least one zone being a zone made of said polymer material, which has a degraded molecular structure at said zone, so as to render said zone opaque in said formed lens, wherein said at least one opaque zone is located within said lens at a distance from a surface of said lens. 
   
   
     11. The lens according to  claim 10  wherein said at least one opaque zone has a diaphragm function. 
   
   
     12. The lens according to  claim 10 , further comprising a plurality of contiguous opaque zones forming a diffraction grating having an optical filter function. 
   
   
     13. The lens according to  claim 10 , further comprising two flat faces. 
   
   
     14. The lens according to  claim 10 , further comprising a flat face and a convex or concave face. 
   
   
     15. The lens according to  claim 10 , further comprising two convex faces. 
   
   
     16. The lens according to  claim 10 , comprising two layers of polymer material assembled against one another, at least one of the layers having said at least one opaque zone having said optical function. 
   
   
     17. A micro-module for capturing images, the micro-module comprising an imager on a semiconductor substrate, and at least one lens according to  claim 10 . 
   
   
     18. The micro-module according to  claim 17  wherein the lens is stuck onto the imager without any lens-holder frame. 
   
   
     19. A formed lens of a polymer material, the lens comprising at least one opaque zone having an optical function, the at least one opaque zone being a zone made of said polymer material, which has a degraded molecular structure at said zone, so as to render said zone opaque in said formed lens, the lens including two layers of polymer material assembled against one another, at least one of the layers having said at least one opaque zone having said optical function, wherein each layer has a convex face and the convex faces of each layer are arranged face to face to form a lenticular cavity. 
   
   
     20. An apparatus, comprising:
 an imaging device having a micro-module to capture images, the micro-module including: 
 an imager on a semiconductor substrate; and 
 at least one lens made of a polymer material, said at least one lens having: 
 (a) at least one opaque zone that includes said polymer material, which has a degraded molecular structure at said zone so as to render said zone opaque, and 
 (b) a region different from said at least one opaque zone, wherein in said region said polymer material maintains said molecular structure to allow light to pass through said region, said at least one opaque zone having an optical function, wherein said at least one opaque zone is located within said lens at a distance from a surface of said lens. 
 
   
   
     21. The apparatus of  claim 20  wherein said imaging device is a web camera, video camera, cellular telephone, or digital camera. 
   
   
     22. The apparatus of  claim 20  wherein said imager is a complementary metal oxide semiconductor (CMOS) imager. 
   
   
     23. The apparatus of  claim 20  wherein said at least one opaque zone is located on a surface of said lens. 
   
   
     24. The apparatus of  claim 20  wherein said optical function is a diaphragm function. 
   
   
     25. The apparatus of  claim 20  wherein said at least one opaque zone includes a plurality of contiguous ones of said at least one opaque zone, said plurality forming a diffraction grating that provides said optical function as an optical filter function.